The present invention provides a RO membrane or a FO membrane comprising a coating layer made of a phospholipid bilayer membrane and formed on a surface of a porous membrane body, having a high water permeate flow rate and salt rejection performance, the membrane being a permselective membrane comprising a porous membrane having a pore size of 5 nm to 50 nm and a coating layer made of a phospholipid bilayer and formed on a surface of the porous membrane, wherein (i) the phospholipid bilayer comprises phospholipid, amphotericin B, and ergosterol; (ii) a content of the amphotericin B is 3 to 20 mol % based on the phospholipid bilayer; (iii) a total content of the ergosterol and the amphotericin B in the phospholipid bilayer is 10 to 30 mol %.